A start-up located in the French Alps near Grenoble is readying a tiny ARM-based Linux single-board computer (SBC) in a USB key form-factor. Calao's USB-9260 USB key-sized SBC measures 3.3 x 1.4 inches (85 x 36 mm). It is based on an Atmel AT91SAM9260 processor, an SoC (system-on-chip) powered by an ARM926EJ-S core clocked at 190MHz. The SoC targets "advanced applications such as GPS application processors," according to Atmel. Here is a Spec sheet PDF. With a 10/100 Ethernet port, firewall usage springs to mind. Other interfaces are 2 USB host ports and room for an expansion card. Which should allow some creative uses.